Amazonspinther dalmata Bührnheim, Carvalho, Malabarba & Weitzman 2008

The presence of three conspicuous black blotches on the base of the dorsal, anal, and caudal fins separates this species from all characid species. Distinguished from all other species of the Cheirodontinae by two uniquely derived characters, the anteriormost proximal radial of the anal fin with an anteriorly extended lamina entering the abdominal cavity, between the distal portions of the 12th to 14th pleural ribs and by the extremely elongate caudal peduncle 27.3-30.2% SL. Can be further diagnosed by having ventral procurrent caudal-fin rays 7-9 and hemal spines of one, two or sometimes three posterior caudal vertebrae directly articulating with the ventral procurrent caudal-fin rays (Ref. 79887).Description: D ii,9; A iii,8; P i10; V i+5+i ; row of longitudinal scales 32; scales between lateral line and pelvic-fin origin 3, 4; precaudal vertebrae including Weberian apparatus 15 (Ref. 79887).

Dorsal soft rays (total): 11; Analsoft rays: 11

The type locality has slow current, muddy substratum, and silty, turbid water with abundant riparian vegetation and with maximum depth of 1.3 m. Also collected in a perceptible current with some submerged vegetation, transparent water, sandy and muddy substratum and riparian vegetation (Ref. 79887).

This species inhabits small streams in the mid-portions of the Purus River basin, as well as the middle and lower regions of the Madeira River drainage in Brazil (Bührnheim et al., 2008).

This species inhabits small clear freshwater streams with slow to moderate current. Amazonspinther dalmata was observed in natural habitats with 1 to 1.3 meters deep, muddy or sandy bottom, and both in transparent and turbid waters with abundant riparian and some submerged vegetation (Bührnheim et al., 2008).

Amazonspinther dalmata can be distinguished from characid species by its color pattern, remarkable by the presence of three conspicuous black blotches on the base of the dorsal, anal, and caudal fins (Bührnheim et al., 2008).

Amazonspinther dalmata is considered a miniature species, once its maximum known size is 19.6 mm of standard length (Bührnheim et al., 2008).

Amazonspinther dalmata is a miniature fish, and it presents several morphological features usually found in miniaturized species: short and incompletely pored lateral line; on row of tooth in the upper and lower jaws; reduction in the number of cusps; absence of lower gill rakers; and in the number of infraorbital bones (presenting only 3). This species also presents a pseudotympanum. Amazonspinther dalmata has a translucent body in life, making several internal organs visible with naked eyes, like the swimbladder and the guts. Diverging from most of the species of the subfamily Cheirodontinae, Amazonspinther dalmata does not present any sexual dimorphism. The body is slightly elongated, the mouth is terminal to slightly subterminal and the snout is short (Bührnheim et al., 2008).

Importance: Aquarium trade, commercial.